refcount.c
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/* GNU Mailutils -- a suite of utilities for electronic mail
Copyright (C) 1999, 2000, 2001, 2003, 2004,
2007 Free Software Foundation, Inc.
This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 3 of the License, or (at your option) any later version.
This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <stdlib.h>
#include <errno.h>
#include <mailutils/errno.h>
#include <mailutils/monitor.h>
#include <mailutils/refcount.h>
struct _mu_refcount
{
unsigned int ref;
mu_monitor_t lock;
};
int
mu_refcount_create (mu_refcount_t *prefcount)
{
int status = 0;
mu_refcount_t refcount;
if (prefcount == NULL)
return MU_ERR_OUT_PTR_NULL;
refcount = calloc (1, sizeof *refcount);
if (refcount != NULL)
{
refcount->ref = 1;
status = mu_monitor_create (&refcount->lock, 0, refcount);
if (status == 0)
{
*prefcount = refcount;
}
else
{
free (refcount);
}
}
else
{
status = ENOMEM;
}
return status;
}
unsigned
mu_refcount_value (mu_refcount_t refcount)
{
return refcount ? refcount->ref : 0;
}
void
mu_refcount_destroy (mu_refcount_t *prefcount)
{
if (prefcount && *prefcount)
{
mu_refcount_t refcount = *prefcount;
mu_monitor_destroy (&refcount->lock, refcount);
free (refcount);
*prefcount = NULL;
}
}
unsigned
mu_refcount_inc (mu_refcount_t refcount)
{
int count = 0;
if (refcount)
{
mu_monitor_wrlock (refcount->lock);
count = ++refcount->ref;
mu_monitor_wrlock (refcount->lock);
}
return count;
}
unsigned
mu_refcount_dec (mu_refcount_t refcount)
{
int count = 0;
if (refcount)
{
mu_monitor_wrlock (refcount->lock);
if (refcount->ref)
count = --refcount->ref;
mu_monitor_wrlock (refcount->lock);
}
return count;
}